Genetic diversity in cocoa (<i>Theobroma cacao</i> L.) plus trees in Tamil Nadu by simple sequence repeat (SSR) markers

Abstract

The range of polymorphism of about 27 cocoa plus trees screened in the major cocoa growing regions of Tamil Nadu were assessed using 10 simple sequence repeat (SSR) markers. The gene diversity, genetic differentiation and genetic similarities were analyzed for the cocoa trees. The number of alleles detected by different primers ranged from 0 to 3 and the level of polymorphism was 0 to 100%. The polymorphism information content (PIC) value ranged from 0.000 to 0.677. The higher the PIC value, the more informative was the SSR marker. Hence, primer mTcCIR33 was found to be highly informative. The Jaccard’s similarity coefficient for the SSR data set varied from 0.39 to 1.00. The SSR marker profiles resulted in nine clusters at nearly 54% similarity. From this study, it could be inferred that the diversity exists in cocoa plantations in Tamil Nadu and can be exploited in crop improvement research.

Keywords: Cocoa, simple sequence repeat (SSR) markers, polymorphism, genetic diversity, breeding.

African Journal of BiotechnologyVol. 12(30), pp. 4747-4753